Nowadays, the input/output (I/O) card widely applied to the storage device typically has a shape factor of a low-profile-half-length peripheral component interconnect express (PCIe) card, as prescribed by the Peripheral Component Interconnect Special Interest Group (PCI-SIG), and such PCIe card does not support advanced features, such as hot plugging, a stable design and the like, or user-defined functions, despite its known shape, function and wire arrangement.